AP_Logger: correct compilation on CubeOrange-periph-heavy

The Stage::LOG_RTC_MSG enumeration value still existing and we weren't handling it as it was being compiled out

libraries/AP_Logger/LogStructure.h

@@ -1339,7 +1339,9 @@ enum LogMessages : uint8_t {
     LOG_UNIT_MSG,
     LOG_MULT_MSG,
     LOG_RALLY_MSG,
+#if AP_RTC_LOGGING_ENABLED
     LOG_RTC_MSG,
+#endif  // AP_RTC_LOGGING_ENABLED
 
     // LOG_MODE_MSG is used as a check for duplicates. Do not add between this and LOG_FORMAT_MSG
     LOG_MODE_MSG,

libraries/AP_Logger/LoggerMessageWriter.cpp

@@ -367,7 +367,7 @@ void LoggerMessageWriter_WriteSysInfo::process() {
         FALLTHROUGH;
 #else
         break;
-#endif  // AP_RTC_ENABLED
+#endif  // AP_RTC_LOGGING_ENABLED
     }
 #if AP_RTC_LOGGING_ENABLED
     case Stage::LOG_RTC_MSG:
@@ -375,7 +375,7 @@ void LoggerMessageWriter_WriteSysInfo::process() {
             return;
         }
         break;
-#endif  // AP_RTC_ENABLED
+#endif  // AP_RTC_LOGGING_ENABLED
     }
 
     _finished = true;  // all done!

libraries/AP_Logger/LoggerMessageWriter.h

@@ -2,6 +2,7 @@
 
 #include "AP_Logger_Backend.h"
 #include <AP_Rally/AP_Rally.h>
+#include <AP_RTC/AP_RTC_config.h>
 
 class LoggerMessageWriter {
 public:
@@ -37,7 +38,9 @@ private:
         PARAM_SPACE_USED,
         RC_PROTOCOL,
         RC_OUTPUT,
+#if AP_RTC_LOGGING_ENABLED
         LOG_RTC_MSG,
+#endif  // AP_RTC_LOGGING_ENABLED
     };
     Stage stage;
 };